Interlayer Dielectric Capping Effect on Thermal Stability of Ni Germanide on Doped Ge-on-Si Substrate for Nano-scale Ge MOSFETs

Analyzed herein is the influence of interlayer dielectric (ILD) oxide capping layer on thermal stability of Ni germanide formed on B-11-, BF2-, and As-doped Ge-on-Si substrates. The thermal stability of Ni germanide has a strong dopant dependence after post-germanidation annealing and the doped samples with ILD have better thermal immunity than those without ILD. The B-11- and BF2- doped samples with ILD oxide capping layer show lower sheet resistance, more uniform interface and more smooth surface images up to 575 degrees C. Therefore, the ILD oxide capping is promising for thermal stability improvement of Ni germanide on doped Ge-on-Si substrate for nano-scale germanium metal oxide semiconductor field effect transistors (Ge MOSFETs).